In humans, the major histocompatibility complex (MHC) is the human leucocyte antigen (HLA) gene cluster on chromosome 6, which is divided into regions termed D, B, C, and A. The D region contains genes for Class II proteins, which are involved in cooperation and interaction between cells of the immune system. The D region has been implicated in many diseases including most autoimmune diseases.
One antibody, L243 (hereafter mL243) is a murine IgG2a anti-HLA-DR antibody. This antibody may be of potential use in the treatment of diseases such as autoimmune diseases by targeting the D region of the mouse HLA gene. mL243 demonstrates potent suppression of in vitro immune function and is monomorphic for all HLA-DR. However, problems exist with the administration of mouse antibodies to human patients, such as the induction of a human anti-mouse antibody (HAMA) response. A need exists for antibodies with the antigenic specificity of mL243, that may be administered to human subjects